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  • 1
    Electronic Resource
    Electronic Resource
    Reduction of thyroid hormone levels by methylsulfonyl metabolites of polychlorinated biphenyl congeners in rats (1998)
    Springer
    Archives of toxicology 72 (1998), S. 541-544 
    Details
    ISSN: 1432-0738
    Keywords: Key words Polychlorinated biphenyl ; Methylsulfonyl metabolite ; Total thyroxine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Male Sprague-Dawley rats received four consecutive intraperitoneal doses of four kinds of methylsulfonyl (MeSO2) metabolites of polychlorinated biphenyl (PCB) congeners: 3-MeSO2-2,2′,3′,4′,5,6-hexachlorobiphenyl (3-MeSO2-CB132); 3-MeSO2-2,2′,3′,4′, 5,5′-hexachlorobiphenyl (3-MeSO2-CB141); 3-MeSO2-2,2′,4′,5,5′,6-hexachlorobiphenyl (3-MeSO2-CB149) and 4-MeSO2-2,2′,4′,5,5′,6-hexachlorobiphenyl (4-MeSO2-CB149). The congeners were major MeSO2-PCBs determined in human milk, liver and adipose tissue, and the aim was to determine their effect on thyroid hormone levels. All four tested MeSO2 metabolites (20 μmol/kg once daily for 4 days) reduced serum total thyroxine levels by 22–44% at a much lower dose than phenobarbital (PB; 431 μmol/kg once daily for 4 days) on days 2, 3, 4 and 7 after the final doses. Total triiodothyronine levels were reduced 37% by treatment with 4-MeSO2-CB149 at day 7. A 30% increase in thyroid weight was produced by 3-MeSO2-CB141 treatment. Total cytochrome P450 content was increased by 3-MeSO2-CB132, 3-MeSO2-CB141 and 3-MeSO2-CB149, but not by 4-MeSO2-CB149. Thus, it is likely that the 3-MeSO2-hexachlorobiphenyls and 4-MeSO2-CB149 could influence the thyroid hormone metabolism by different mechanism(s). The results show that tested 3- and 4-MeSO2 metabolites of PCB congeners reduce thyroid hormone levels much more than PB in rats. Our finding suggests that the metabolites may act as endocrine-disrupters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050540
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  • 2
    Electronic Resource
    Electronic Resource
    Genetically mediated induction of aryl hydrocarbon hydroxylase activity in human lymphoblastoid cells by polychlorinated dibenzofuran isomers and 2,3,7,8-tetrachlorodibenzo-p-dioxin (1985)
    Springer
    Archives of toxicology 56 (1985), S. 230-235 
    Details
    ISSN: 1432-0738
    Keywords: Polychlorinated dibenzofurans (PCDFs) ; 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) ; Aryl hydrocarbon hydroxylase (AHH) inducibility ; Toxicity ; Human lymphoblastoid cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aryl hydrocarbon hydroxylase(AHH)-inducing potency of toxic polychlorinated aromatic hydrocarbons such as polychlorinated dibenzofuran (PCDF) isomers, 3,4,5,3′,4′,5′-hexachlorobiphenyl (HCB) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was investigated in human lymphoblastoid cell lines with different AHH inducibility for 3-methylcholanthrene (3-MC) obtained from healthy subjects. Each of the cell lines was treated with eitht individual PCDF isomers, TCDD, and HCB at doses of 1.9–15 ng/ml of culture medium, 1.9–7.5 ng/ml and 95 ng/ml, respectively. Lymphoblastoid cell lines were arbitrarily classified into three groups based on their AHH inducibilities with 3-MC (2.5 μM); low (3-MC/ control=I〈3), middle (3〈=I〈6) and high (I〉=6). Degrees of the enzyme inducibilities of the organochlorine compounds proportionally increased with those for 3-MC. AHH inducibilities with 2,3,4,7,8-pentachlorodibenzofuran(2,3,4,7,8-PCDF), 1,2,3,4,6,7-hexachlorodibenzofuran(1,2,3.4,6,7-HCDF) and 1,2,3,4,7,8-hexachlorodibenzofuran(1,2,3,4,7,8-HCDF) were comparable to those of TCDD at doses of 7.5 ng/ ml, and about twice as high as those of 2,3,7,8-tetrachlorodibenzofuran (TCDF), at the same dose, HCB, at a dose of 95 ng/ ml, did not induce enzyme activity. The experimental evidence indicated that AHH inducibility by the organochlorine compounds reflected the genetic susceptibility of the cells to the phenomenon of induction, and PCDF isomers found at relatively high concentrations in tissues of mammals exerted the highest values of AHH induction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295159
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  • 3
    Electronic Resource
    Electronic Resource
    Genetically mediated induction of aryl hydrocarbon hydroxylase activity in mice by polychlorinated dibenzofuran isomers and 2,3,7,8-tetrachlorodibenzo-p-dioxin (1985)
    Springer
    Archives of toxicology 56 (1985), S. 226-229 
    Details
    ISSN: 1432-0738
    Keywords: Polychlorinated dibenzofurans (PCDFs) ; 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) ; Aryl hydrocarbon hydroxylase (AHH) activity ; AHH responsiveness ; Mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Hepatic aryl hydrocarbon hydroxylase (AHH)-inducing potency of toxic polychlorinated aromatic hydrocarbons such as polychlorinated dibenzofurans (PCDFs), 3,4,5,3′,4′,5′-hexachlorobiphenyl (HCB) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was studied in four inbred strains of mice with different phenotypes of Ah locus, i.e., AHH-responsive strains: C57BL/6N and AKR/Ms Qdj, and AHH-nonresponsive strains: DBA/2Cr Slc and Qdj; DDD. Eight individual PCDF isomers or TCDD were administered IP in doses of 30 μg/kg; HCB was given in a dose of 120 μg/kg. In AHH-nonresponsive strains of mice, only TCDD significantly induced hepatic AHH activity, while in AHH-responsive strains, 2,3,7,8-tetrachlorodibenzofuran(2,3,7,8-TCDF), 1,2,3,7,8-pentachlorodibenzofuran(1,2,3,7,8-PCDF) 2, 3, 4, 7, 8-pentachlorodibenzofuran (2, 3,4, 7, 8-PCDF), and TCDD significantly enhanced the enzyme activity, and the induced AHH activities with the three PCDF isomers were about 30–65% of those of TCDD. These results indicate that AHH responsiveness in mice segregates with the induction of AHH activity by PCDF isomers and may also segregate with the toxic potency of the isomers; i.e., toxic potencies of 2,3,7,8-TCDF, 1,2,3,7,8-PCDF, and 2,3,4,7,8-PCDF in AHH-responsive strains of mice may be much greater than those in AHH-nonresponsive strains of mice. Taking into account both the potent AHH inducibility and the high bioaccumulation of 2,3,7,8-TCDF, 1,2,3,7,8-PCDF, and 2,3,4,7,8-PCDF, these three PCDF isomers should be given greater attention with regard to environmental contamination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295158
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